The synthetic cationic lipid diC14 activates a sector of the Arabidopsis defense network requiring endogenous signaling components

CAMBIAGNO D.A.; LONEZ C.; RUYSSCHAERT J.M.; ALVAREZ M.E.

MOLECULAR PLANT PATHOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2015 vol. 16 p. 963 - 972

1464-6722

Natural and synthetic elicitors have significantly contributed to the study of plant immunity.Pathogen-derived proteins and carbohydrates, that bind to immune receptors allowed fine dissectionof some defense pathways. Lipids of different nature that act as defense elicitors have also beenstudied, but their specific effects have been less characterized, and their receptors have not beenidentified. In animal cells, nanoliposomes of the synthetic cationic lipid 3-tetradecylamino-tertbutyl-N-tetradecylpropionamidine (diC14) activate the TLR4-dependent immune cascade. We hereinvestigated if this lipid induces Arabidopsis defense responses. At the local level, diC14 activatedearly and late defense gene markers (FRK1, WRKY29, ICS1 and PR1) acting in a dose dependentmanner. This lipid induced the salicylic acid (SA)-, but not jasmonic acid (JA)-, dependent pathwayand protected plants against Pseudomonas syringae pv. tomato (Pst), but not Botrytis cinerea.diC14 was not toxic for plant or pathogen, and potentiated pathogen-induced callose deposition. Atthe systemic level, diC14 induced PR1 expression and conferred resistance against Pst. diC14-induced defense responses required the signaling protein EDS1 but not NDR1. Curiously, the lipidinduceddefense genes expression were lower in fls2/efr/cerk1 triple mutant while still unchanged inthe single mutants. The amidine headgroup and chain length were important for its activity. Giventhe robustness of the responses triggered by diC14, its specific action on a defense pathway and therequirement of well-known defense components, this synthetic lipid is emerging as a useful tool toinvestigate initial events involved in plant innate immunity.